Installation of a standard AC electrical system in a new residence or commercial site occurs in three phases, corresponding to the building construction. The rough phase corresponds to rough framing of the building, prior to attachment of wall panels to the frame. During this phase, blue boxes or similar electrical boxes are mounted to wall studs at predetermined locations, so that outlets are 18″ and switches are 36″ from the floor. Various box types are available, such as single-, double-, triple- or quadruple-wide configurations, among others. After the boxes are installed, a journeyman electrician, following a predetermined layout, routes Romex™ brand or equivalent power cables through the framing to the appropriate boxes. A typical power cable has two solid core insulated conductors and a ground conductor, all surrounded by a non-metallic sheath. The power cable is fed through openings in the rear or sides of the electrical boxes. The journeyman typically labels the conductors by writing a code on the insulation that indicates the wiring connectivity and the type of module to be installed in each box. Then these cables are folded back into the boxes, unterminated, so as to be out of the way until the next phase. After all of the electrical wiring is routed in this manner, the electrical subcontractors leave the construction site, waiting for other subcontractors to finish their tasks.
The makeup phase corresponds to wall panel installation and painting. During this phase, the journeyman returns to the construction site to install modules into the electrical boxes. The journeyman retrieves the cable from each box, reviews the labeling, and connects the cable conductors to the appropriate module. One module choice is a duplex outlet that receives standard two-prong or three-prong grounded AC plugs. The outlet can be wired fall-hot, where each outlet is always connected to power, or half-hot, where one outlet is connected to power under control of a wall switch. Another module choice is a switch, which can be a standard on/off switch, a three-way switch or a dimmer switch, for example. After conductors are wired to a module, the module and attached conductors are pushed into the electrical box and the module is attached to the top and bottom of the box with screws. Once all modules are installed, the general contractor verifies the dwelling wiring against the electrical plans. If all of the wiring is correct, power can be connected to the dwelling for the first time.
The final phase corresponds to construction thing and finishing work. During the trim phase, face plates are mounted over the open-end of the electrical boxes, completing the standard electrical wiring process.